Antique Japanese Katana, Signed "Yokoyama Kōzuke Daijō Fujiwara Sukesada" (横山上野大掾藤原祐定) — NBTHK Hozon Tōken, by the Master Who Revived Bizen Osafune Swordsmithing

A densely forged itame jigane and the world-famous "kaninotsume" (crab-claw) gunome-chōji hamon, on a blade shortened from an original ~79 cm to a versatile 68.1 cm

We are pleased to present a magnificent Shintō-era katana by the celebrated master Yokoyama Kōzuke Daijō Fujiwara Sukesada (横山上野大掾藤原祐定) of Bizen Osafune, formally certified as Hozon Tōken (Preservation Sword) by the NBTHK (Nihon Bijutsu Tōken Hozon Kyōkai) in February 2025. Originally crafted as a massive long sword of approximately 79 cm, the blade was later shortened (suriage) to a versatile 68.1 cm. In pristine condition, it embodies the absolute pinnacle of traditional Bizen-den craftsmanship.

On the smith — Kōzuke Daijō Sukesada (上野大掾祐定)

Real name Yokoyama Heibei, Kōzuke Daijō Sukesada was the son of Shichibei-jō Sukesada and is celebrated as the premier founding master (shodai) of the Shintō-era Sukesada lineage. Sukesada is revered as the single greatest contributor to Bizen swordsmithing in the Edo period: following the catastrophic Yoshii River flooding in the late 16th century that devastated the Osafune workshops, he tirelessly revived the famous school and restored it to nationwide prominence. In 1664 (Kanbun 4), he was awarded the prestigious court title Kōzuke Daijō in recognition of his supreme craftsmanship.

Note on the signature: Due to suriage (shortening of the tang in a later period), the inscription is partially trimmed. The sashi-omote (front) reads "Yokoyama Kōzuke Daijō Fuji..." (originally "Yokoyama Kōzuke Daijō Fujiwara Sukesada"), while the sashi-ura (back) reads "Bizen Osafune..." (originally "Bizen Osafune Jūnin").

Workmanship and condition

Freshly and beautifully polished throughout, the blade retains exceptional health, entirely free of flaws, chips, or rust. The jigane is a densely kneaded, exquisite itame-hada (wood-grain pattern), full of moisture and refined texture. The hamon is a striking gunome-chōji (irregular clove-shaped pattern) featuring sharp, claw-like peaks known as kaninotsume (crab claws) — the world-famous hallmark temper pattern exclusive to the Sukesada line. Rich yō activity permeates the interior of the temper line, leading into a spirited midare-komi bōshi.

Form

A beautifully proportioned shinogi-zukuri katana featuring a graceful sori (curvature) of 1.5 cm paired with a nagasa (edge length) of 68.1 cm. Tapering smoothly from a robust motohaba of 29.0 mm down to 21.5 mm at the sakihaba, the blade displays a dignified, perfectly balanced silhouette with a strong classical presence in the hand.

The mounting (shirasaya)

The blade is safely preserved in a clean, high-grade traditional shirasaya (plain wood resting scabbard), safeguarding the freshly polished steel and elegant profile for generations of appreciation.

Featuring the rare kaninotsume hamon, a historic shortened tang with genuine signature, and freshly granted NBTHK Hozon certification, this Kōzuke Daijō Sukesada katana offers a rare chance to own a museum-grade masterpiece from the heart of Bizen Osafune.

Specifications

• Type: Katana (刀), shinogi-zukuri with iori-mune; suriage, zaimei (signed, shortened); Shintō era (Edo period)
• Smith: Yokoyama Kōzuke Daijō Fujiwara Sukesada (横山上野大掾藤原祐定), real name Yokoyama Heibei; Bizen Osafune
• Signature (mei): Front: "Yokoyama Kōzuke Daijō Fuji..." (横山上野大掾藤...) [suriage-mei]; Back: "Bizen Osafune..." (備前長船...) [suriage-mei]
• Jigane: Densely kneaded, exquisite itame-hada
• Hamon: Gunome-chōji with kaninotsume (crab-claw) pattern, active yō
• Length of edge (nagasa): 68.1 cm, originally approx. 79 cm prior to suriage (approx. 26.81 in / approx. 2 shaku 2 sun 5 bu)
• Curvature (sori): 1.5 cm (approx. 0.59 in)
• Width at base (motohaba): 29.0 mm (approx. 1.14 in)
• Thickness at base (motokasane): 6.6 mm (approx. 0.26 in)
• Width at tip (sakihaba): 21.5 mm (approx. 0.85 in)
• Thickness at tip (sakikasane): 4.7 mm (approx. 0.19 in)
• Peg holes (mekugi-ana): 3
• Weight (blade only): 730 g
• Condition: Excellent; beautifully polished throughout, free of rust, chips, or flaws
• Mounting: Shirasaya
• Certification: NBTHK Hozon Tōken
• Registration No.: Tokyo No. 328367 (東京 第328367号)